So as to produce electrical power, it is known to use electric machines powered by gas turbines comprising a burner assembly which is ignited and started using a natural gas as fuel and then, when the electric machine has exceeded a predetermined value of load, is fed by a so called synthesis gas or syngas, that is a fuel gas rich in hydrogen and having a relatively low calorific value (low-BTU), for example a fifth of the calorific value of natural gas.
However, the use of the two different types of fuel gas for starting the burner assembly of the turbine is unsatisfactory, since it is necessary to envisage double connecting systems to deliver fuel gas from different sources, and it is necessary to bear a relatively high fixed cost for the natural gas supply contract, while the number of times the burner assembly is ignited is in effect relatively low.